Preheat your oven to 350°F (175°C).
In a medium mixing bowl, combine graham cracker crumbs, sugar, and melted butter. Mix well until fully combined.
Press the crumb mixture firmly into the bottom of the springform pan to form an even layer. Bake in the preheated oven for 8-10 minutes until set. Remove and let cool.
In a large mixing bowl, beat the softened cream cheese with an electric mixer until smooth and creamy.
Gradually add granulated sugar, vanilla extract, and mashed bananas, mixing until well combined.
Add the eggs one at a time, mixing on low speed after each addition until just combined. Avoid overmixing.
Stir in the sour cream and lemon juice until smooth.
Pour the cheesecake filling over the cooled crust in the springform pan and smooth the top with a rubber spatula.
Bake in the oven for 50-60 minutes, or until the center is set but still slightly jiggly. Turn off the oven and crack the door open, allowing the cheesecake to cool inside for about an hour.
Remove the cheesecake from the oven and let it cool to room temperature. Refrigerate for at least 4 hours (preferably overnight) to fully set.
Before serving, garnish with sliced banana, whipped cream, and chopped nuts if desired.